Process development usually has an indispensable period of yield-learning. The length of the period is highly dependent on identification of the root causes of yield-limiting defects and thus failure analysis plays an important role in the yield improvement process. This paper presents the failure analysis of yield-limiting defects in 0.15µm process development. The failure analysis involves failure mode categorization by MOSAID tester, defective contact identification by contact-level Passive Voltage Contrast (PVC) technique and subsequent Focus Ion Beam (FIB) cross-section followed by Transmission Electron Microscopy (TEM) analysis. Finally, the root causes for the yield-limiting defects were identified.